My rev counter has been on the blink for a couple of years now, some times you drive her and it works other times it wont.
On the odd time a have smacked the dash and it seems to work but not sure if its just luck really.
Brought another set of clocks which were meant to work but nothing!!! is there any thing else that would make it stop working or any way of testing things.
I just miss seeing it move Lol.
Thanks dave

 

Turn the boost up

 

The tracks can cause problems but as you have swapped yours, check the green wire this connects to the coil.

Martin